We are given a triangle $ABD$ with angle $A = 62^\circ$, angle $B = 14^\circ$, and angle $D = 31^\circ$. We need to find the reflex angle $BCD$.

GeometryTrianglesAnglesReflex Angles
2025/5/11

1. Problem Description

We are given a triangle ABDABD with angle A=62A = 62^\circ, angle B=14B = 14^\circ, and angle D=31D = 31^\circ. We need to find the reflex angle BCDBCD.

2. Solution Steps

First, we find the angle ADBADB.
The sum of angles in a triangle is 180180^\circ. Therefore, in triangle ABDABD,
A+B+D=180A + B + D = 180^\circ
62+14+D=18062^\circ + 14^\circ + D = 180^\circ
76+D=18076^\circ + D = 180^\circ
ADB=18076=104ADB = 180^\circ - 76^\circ = 104^\circ.
Next, we observe that points A,C,BA, C, B are collinear, implying that ACBACB is a straight line, meaning that angle ACB=180ACB = 180^\circ. Also C,D,AC, D, A are collinear, implying that CDACDA is a straight line, meaning that angle CDA=180CDA = 180^\circ.
In triangle BCDBCD, the sum of the angles is 180180^\circ, i.e., DBC+BCD+CDB=180DBC + BCD + CDB = 180^\circ.
Therefore, 14+BCD+31=18014^\circ + BCD + 31^\circ = 180^\circ.
45+BCD=18045^\circ + BCD = 180^\circ
BCD=18045=135BCD = 180^\circ - 45^\circ = 135^\circ.
However, the question asks for the reflex angle BCDBCD, which is the angle greater than 180180^\circ.
The reflex angle BCD=360BCDBCD = 360^\circ - \angle BCD.
Reflex angle BCD=360(180(14+BDC))=360(180(14+BDC))BCD = 360^\circ - (180^\circ - (14^\circ + \angle BDC)) = 360^\circ - (180^\circ - (14^\circ + \angle BDC)).
Since the angles BCDBCD and BCABCA form a straight line, we have BCA=180\angle BCA = 180^\circ.
Since ACDACD is a straight line, we know that ACD=180\angle ACD = 180^\circ.
Also, ACB\angle ACB is a straight line, so ACB=180\angle ACB = 180^\circ.
Therefore ACB=ACD=180\angle ACB = \angle ACD = 180^\circ.
Since we have a triangle ABDABD, we know that ADB=180(62+14)=18076=104\angle ADB = 180^\circ - (62^\circ + 14^\circ) = 180^\circ - 76^\circ = 104^\circ.
The angle at CC can be found by looking at angles around the point CC.
Let the angle ACD=xACD = x and the angle BCD=yBCD = y.
Also, ACD+BCD=360ACD + BCD = 360.
Then x+y=360x + y = 360.
So, the reflex angle BCD=360xBCD = 360 - x.
We have the triangle ABCABC. We have A=62A=62, B=14B=14, so C=180(62+14)=18076=104C=180-(62+14) = 180 - 76 = 104.
BCD=104+62+14+31=18076=104BCD = 104+62+14+31=180-76=104
We know that BCA+BCD=360\angle BCA + \angle BCD = 360^\circ.
First, calculate BCA\angle BCA. BCA=180BACABC=1806214=104\angle BCA = 180 - \angle BAC - \angle ABC = 180 - 62 - 14 = 104.
Now, we have BCD=180(CBD+CDB)=180(14+31)=18045=135\angle BCD = 180 - (\angle CBD + \angle CDB) = 180 - (14 + 31) = 180 - 45 = 135.
The reflex BCD=360135=225\angle BCD = 360 - 135 = 225^\circ.

3. Final Answer

225

Related problems in "Geometry"

The problem states that the area of triangle OFC is $33 \text{ cm}^2$. We need to find the area of t...

AreaTrianglesSimilar TrianglesRatio and Proportion
2025/6/6

We are asked to calculate the volume of a cylinder. The diameter of the circular base is $8$ cm, and...

VolumeCylinderRadiusDiameterPiUnits of Measurement
2025/6/5

The problem asks us to construct an equilateral triangle with a side length of 7 cm using a compass ...

Geometric ConstructionEquilateral TriangleCompass and Straightedge
2025/6/4

The problem asks to construct an equilateral triangle using a pair of compass and a pencil, given a ...

Geometric ConstructionEquilateral TriangleCompass and Straightedge
2025/6/4

The problem asks to find the value of $p$ in a triangle with angles $4p$, $6p$, and $2p$.

TriangleAnglesAngle Sum PropertyLinear Equations
2025/6/4

The angles of a triangle are given as $2p$, $4p$, and $6p$ (in degrees). We need to find the value o...

TrianglesAngle Sum PropertyLinear Equations
2025/6/4

The problem asks to construct an equilateral triangle with sides of length 7 cm using a compass and ...

ConstructionEquilateral TriangleCompass and Straightedge
2025/6/4

We are given two polygons, $P$ and $Q$, on a triangular grid. We need to find all sequences of trans...

TransformationsRotationsReflectionsTranslationsGeometric TransformationsPolygons
2025/6/4

We need to describe the domain of the following two functions geometrically: 27. $f(x, y, z) = \sqrt...

3D GeometryDomainSphereHyperboloidMultivariable Calculus
2025/6/3

We need to find the gradient of the line passing through the points $P(2, -3)$ and $Q(5, 3)$.

Coordinate GeometryGradientSlope of a Line
2025/6/3